Sliding doors (plate-like object) open and close an opening of a window or furniture by moving in a left and right direction, often guided by a guide apparatus. Well-known are guide apparatus which open an opening by guiding the sliding door from a closed position (set position) to an opening preparation position (preparation position) located in front of or behind the closed position, and then from the opening preparation position to an open position (non-set position) located to the left or right of the opening preparation position.
Japanese Patent Application Laid-Open No. H7-269217 discloses an opening and closing apparatus for a window of a house. The opening and closing apparatus comprises two identically-shaped doors. One of the doors is immovably fixed in the right side of the window. The other, being provided as a sliding door, is movable in a left and right direction and opens and closes an opening adjacent to the fixed door. When the sliding door is in a closed position, it is flush with the fixed door providing a good appearance. To open the opening, the sliding door is pulled to the front from the closed position to an opening preparation position and moved to an open position, where it is overlapped with the fixed door located in the right direction. To close the opening, in the reverse order, the sliding door is moved from the open position to the opening preparation position in the left direction and pushed to the rear to the closed position, where it is flush with the fixed door. A guide apparatus for bringing about such a sliding door movement comprises rails disposed on upper and lower edges of a window, upper and lower runners which run along the rails and pantograph mechanisms for connecting the runners to upper and lower edges of the sliding door respectively. The pantograph mechanisms are folded when the sliding door is in the closed position. When the sliding door is pulled to the front, the pantograph mechanisms extend and the sliding door is moved to the open position being supported by the extended pantograph mechanisms.
Japanese Utility Model Publication No. S59-26066 discloses furniture including three sliding doors. Sliding doors at the left and right move guided along first tracks disposed on upper and lower edges of the opening to open and close left and right opening sections, respectively. A sliding door in the middle moves guided along second tracks disposed on upper and lower edges of the opening to open and close a middle opening section. The second tracks are parallel to the first tracks and located behind the first tracks. Upper and lower runners which run on the second track are connected to upper and lower edges of the sliding door in the middle respectively by means of pantograph mechanisms. When the sliding door in the middle is in a closed position being flush with the sliding doors to the left and right, the pantograph mechanism is extended. When the sliding door in the middle is pushed to the rear, the pantograph mechanism is folded, which enables the sliding door to move to left and right open positions.
In apparatus disclosed in Japanese Patent Application Laid-Open No. H7-269217 and Japanese Utility Model Publication No. S59-26066 as described above, the complex pantograph mechanism exists between the sliding door and the runners. Since the pantograph mechanism constantly supports load of the sliding door including when the door is moving to the open position, it is prone to failure.